The main features are:
(1) A cheat mode, where the program cheats on the player. One or more numbers on the board are incorrect and the player has to figure out which ones they are!
(2) msec accuracy in timing your games. Now you can really know how well you are doing and how much you are improving.
(3) Allow for mistakes. Who says the game has to end when you click on a bomb?
(4) Right click anywhere on the board for a new game.